Tissue ablation refers to the destruction of tissue. The most ancient form of tissue ablation is surgery, whereby pathological tissues are physically removed from the body.
Over the last 40 to 50 years, considerable progress has been made toward ablative techniques that are both minimally invasive i.e., do not require open surgery, and affect very localized tissue areas. Examples include Radio Frequency (RF) , cryo-ablation, and laser ablation of tumors that can develop anywhere in the body; RF, cryo-ablation, and laser ablation of blood vessels; RF and laser ablation of various cardiac structures, especially in the left atrium of the heart for the treatment of atrial fibrillation and other conduction disorders. Most recently it has been demonstrated that ablation of the nerves supplying the renal arteries can lead to dramatic reductions in blood pressure in patient populations unresponsive to drug based blood pressure controls.
One significant problem associated with current ablative technologies is that they still destroy whole volumes of tissue without regard to their cellular content. This can lead to other types of dysfunction that are not intended consequences of the therapy. An example of this is ablation of the tissues surrounding the openings of the pulmonary veins into the left atrium in the treatment of atrial fibrillation. The thermal heat of RF ablation, or the freezing of tissue in cryo-ablation destroys not only the neurons that the clinician wants to destroy, but also a volume of otherwise useful muscular tissue of the atrium. The same is true for the new technique of renal ablation wherein the entire wall of the renal artery is thermally coagulated in certain areas in order to destroy the nerves located mainly in the outer covering of the artery known as the adventitia. This may leave the artery less compliant than it would be otherwise, and also cause areas of stenosis that may restrict normal blood flow to the kidneys. Another unwanted side effect of many of the ablative technologies is that they cause significant pain.
What is needed are improved therapy delivery systems and methods of improved treatment that overcome the short comings of the previous systems.